Navigation system



FIG. 1 is an isometric view showing the top, front and side of my invention;

FIG. 2 is a front elevation view of my invention;

FIG. 3 is a back elevation view of my invention;

FIG. 4 is a left-side elevation view of my invention;

FIG. 5 is a right-side elevation view of my invention;

FIG. 6 is a top elevation view of my invention; and,

FIG. 7 is a bottom elevation view of my invention. 

The ornamental design for a navigation system, as shown and described. 